RESUMO
The goal of this study was to investigate the effect of audio listened to through headphones on subjectively reported human focus levels, and to identify through objective measures the properties that contribute most to increasing and decreasing focus in people within their regular, everyday environment. Participants (N = 62, 18-65 years) performed various tasks on a tablet computer while listening to either no audio (silence), popular audio playlists designed to increase focus (pre-recorded music arranged in a particular sequence of songs), or engineered soundscapes that were personalized to individual listeners (digital audio composed in real-time based on input parameters such as heart rate, time of day, location, etc.). Audio stimuli were delivered to participants through headphones while their brain signals were simultaneously recorded by a portable electroencephalography headband. Participants completed four 1-h long sessions at home during which different audio played continuously in the background. Using brain-computer interface technology for brain decoding and based on an individual's self-report of their focus, we obtained individual focus levels over time and used this data to analyze the effects of various properties of the sounds contained in the audio content. We found that while participants were working, personalized soundscapes increased their focus significantly above silence (p = 0.008), while music playlists did not have a significant effect. For the young adult demographic (18-36 years), all audio tested was significantly better than silence at producing focus (p = 0.001-0.009). Personalized soundscapes increased focus the most relative to silence, but playlists of pre-recorded songs also increased focus significantly during specific time intervals. Ultimately we found it is possible to accurately predict human focus levels a priori based on physical properties of audio content. We then applied this finding to compare between music genres and revealed that classical music, engineered soundscapes, and natural sounds were the best genres for increasing focus, while pop and hip-hop were the worst. These insights can enable human and artificial intelligence composers to produce increases or decreases in listener focus with high temporal (millisecond) precision. Future research will include real-time adaptation of audio for other functional objectives beyond affecting focus, such as affecting listener enjoyment, drowsiness, stress and memory.
RESUMO
OBJECTIVE Glioblastoma multiforme (GBM) is composed of cells that migrate through the brain along predictable white matter pathways. Targeting white matter pathways adjacent to, and leading away from, the original contrast-enhancing tumor site (termed leading-edge radiosurgery [LERS]) with single-fraction stereotactic radiosurgery as a boost to standard therapy could limit the spread of glioma cells and improve clinical outcomes. METHODS Between December 2000 and May 2016, after an initial diagnosis of GBM and prior to or during standard radiation therapy and carmustine or temozolomide chemotherapy, 174 patients treated with radiosurgery to the leading edge (LE) of tumor cell migration were reviewed. The LE was defined as a region outside the contrast-enhancing tumor nidus, defined by FLAIR MRI. The median age of patients was 59 years (range 22-87 years). Patients underwent LERS a median of 18 days from original diagnosis. The median target volume of 48.5 cm3 (range 2.5-220.0 cm3) of LE tissue was targeted using a median dose of 8 Gy (range 6-14 Gy) at the 50% isodose line. RESULTS The median overall survival was 23 months (mean 43 months) from diagnosis. The 2-, 3-, 5-, 7-, and 10-year actual overall survival rates after LERS were 39%, 26%, 16%, 10%, and 4%, respectively. Nine percent of patients developed treatment-related imaging-documented changes due to LERS. Nineteen percent of patients were hospitalized for management of edema, 22% for resection of a tumor cyst or new tumor bulk, and 2% for shunting to treat hydrocephalus throughout the course of their disease. Of the patients still alive, Karnofsky Performance Scale scores remained stable in 90% of patients and decreased by 1-3 grades in 10% due to symptomatic treatment-related imaging changes. CONCLUSIONS LERS is a safe and effective upfront adjunctive therapy for patients with newly diagnosed GBM. Limitations of this study include a single-center experience and single-institution determination of the LE tumor target. Use of a leading-edge calculation algorithm will be described to achieve a consistent approach to defining the LE target for general use. A multicenter trial will further elucidate its value in the treatment of GBM.
